What is the reason for severe water accumulation in the rear seats of a 2012 Tiguan?
3 Answers
The severe water accumulation in the rear seats of a 2012 Tiguan is caused by the failure of the door waterproof membrane. The hazards of a water-damaged vehicle include the following 2 points: 1. Interior impact: Materials such as carpets and seats inside the vehicle may deform, become rough, and produce odors due to prolonged soaking, leading to bacterial growth. The wiring harness under the carpet may retain heavy moisture, causing short circuits due to dampness. These soaked components are best replaced to avoid post-flooding complications. 2. Door panel impact: The door panels contain sound insulation foam, which needs to be replaced after water damage. The wheel bearings must also be replaced because the bearing seals contain lubricating oil. If not replaced, the oil can corrode and deteriorate, losing its lubricating function and affecting driving safety.
I've been running an auto repair shop for over a decade and have handled many old Tiguan models. I've seen plenty of rear seat water accumulation issues. The Tiguan has a common flaw—the sunroof drain holes are designed at the rear ceiling area. After 12 years, the rubber tubes become hardened with age, and the drain outlets easily get completely clogged with mud and debris. When it rains, the water can't drain properly and flows down the A-pillar to the rear floor. Additionally, its rear door seals are prone to deformation, allowing water to seep through door panel gaps during car washes or heavy rain. Once, I encountered a case where an owner spilled drinks on the back seat without cleaning it up, which ended up blocking the air conditioning condensate drain pipe under the seat, making the water accumulation even worse. This water pools beneath the carpet and can grow mold in just three days during summer. You need to quickly remove the seats to dry them out and unclog the drain pipes while you're at it.
Last week, my 2012 Tiguan's rear seats also got flooded! At first, I thought my kid spilled a drink, but when I touched the carpet, I found the entire area under the right rear seat was soaked. After lifting it at the repair shop, the mechanic said the trunk seal had cracked, allowing rainwater to seep in along the rear window. He also mentioned that the sheet metal seams near the Tiguan's rear wheel arches are prone to separation, letting water in under pressure when wading. The most surprising issue was the A/C drain hose—it turns out the soft tube under the rear seats had aged and detached, leaking all the condensation onto the floor when the A/C was on. Now, with a new seal, silicone-sealed seams, it cost over 800 yuan.
